Jan Cock Blomhoff (Amsterdam, 5 August 1779 – Amersfoort, 15 August 1853) was director ("opperhoofd") of Dejima, the Dutch trading colony in the harbour of Nagasaki, Japan, 1817 - 1824, succeeding Hendrik Doeff.
During his first stay on the island (1809–1813) he had an affair with a Japanese woman and the couple had a child, who died in 1813.
When he arrived in Dejima for the second time in August 1817 he was accompanied by his wife Titia Bergsma, whom he had married in 1815, his son Johannes, and Petronella Muns, a Dutch wetnurse and an Indonesian maid. The ladies and the little boy were not allowed to stay. In the short time they stayed there, till December 1817, they were often drawn by artists, who had never seen other than Japanese women, and 500 different prints widely circulated throughout the country.